I have a 91 AWD, with 219000 miles on it. The motor has less but I am not sure when it was rebuilt/replaced. I am also not sure if the trans has been rebuilt or replaced ever.
My question is this. How do I or should I flush my fluid? I changed the filter and seal on the trans about three thousand miles ago. I have also towed a 17' Casita with it since I replaced the filter, up and down a mountain pass. Also don't have an external transmission cooler other than the stock radiator. I only ask because my fluid is a little dark, i think it has something to do with towing the trailer.
My thoughts were to disconnect the line to the radiator and drain it into an empty bucket. While having a line connected to the radiator inlet sucking fluid from a bucket full of new ATF.
Is there enough suction in the trans to pull fluid from the second bucket? In my mind i see this as a perfect flush because there are no other chemicals involved, and in theory the fluid level will always stay the same.